From: Dongliang Mu <mudongliangabcd@xxxxxxxxx> [ Upstream commit a942da24abc5839c11a8fc2a4b7cb268ea94ba54 ] Syzkaller hit 'WARNING: kobject bug in erofs_unregister_sysfs'. This bug is triggered by injecting fault in kobject_init_and_add of erofs_unregister_sysfs. Fix this by adding sanity check for kobject in erofs_unregister_sysfs Note that I've tested the patch and the crash does not occur any more. Link: https://lore.kernel.org/r/20220315132814.12332-1-dzm91@xxxxxxxxxxx Signed-off-by: Dongliang Mu <mudongliangabcd@xxxxxxxxx> Fixes: 168e9a76200c ("erofs: add sysfs interface") Reviewed-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx> Reviewed-by: Chao Yu <chao@xxxxxxxxxx> Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/erofs/sysfs.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c index dac252bc9228..f3babf1e6608 100644 --- a/fs/erofs/sysfs.c +++ b/fs/erofs/sysfs.c @@ -221,9 +221,11 @@ void erofs_unregister_sysfs(struct super_block *sb) { struct erofs_sb_info *sbi = EROFS_SB(sb); - kobject_del(&sbi->s_kobj); - kobject_put(&sbi->s_kobj); - wait_for_completion(&sbi->s_kobj_unregister); + if (sbi->s_kobj.state_in_sysfs) { + kobject_del(&sbi->s_kobj); + kobject_put(&sbi->s_kobj); + wait_for_completion(&sbi->s_kobj_unregister); + } } int __init erofs_init_sysfs(void) -- 2.34.1
